Integrated circuits typically are formed from semiconductor chips or dice supporting respective electronic circuits. Integrated circuits typically are packaged in hermetically sealed or plastic molded packages to prevent environmental degradation that otherwise might be caused by, for example, humidity, contaminants, and electrically charged species. In addition, current trends in integrated circuit design are increasing device functionality and shrinking device size. These trends are leading to an increase in the power dissipation requirements of semiconductor dice. For this reason, integrated circuits typically are packaged on carrier structures (e.g., flexible polyimide carriers, glass reinforced epoxy carriers, and ceramic circuit carriers) that include heat dissipation features for cooling the integrated circuit dice mounted within the packages.
In one common power dissipation approach, an integrated circuit package includes a metal heat sink that is bonded or laminated to a circuit carrier. In some approaches, the bottom (or back) side of the integrated circuit die (i.e., the side that is free of any electrical signal connections) is attached to the metal heat sink with an epoxy-based adhesive, which may contain thermally conductive particles that increase the thermal conductivity between the integrated circuit chip and the heat sink. In other approaches, the bottom side of the integrated circuit die is attached to the circuit carrier surface at locations that are electrically and thermally connected to one or more heat spreading elements. In one integrated circuit system of this type, the heat spreading elements are thermal solder balls, which are attached to the bottom of the package. This system also includes a silicone-based layer that is screened onto the top face of a semiconductor die during packaging to increase thermal conduction between the electronic component and an overlying heat spreader.